(1) Field of the Invention
The present invention relates to a magnetic head slider and a magnetic disc drive.
(2) Description of Related Art
In a magnetic disc drive such as a hard disc or the like, a servo data is recorded along a recording track formed in the magnetic disc, and the servo data is read by a magnetic head slider flying above the magnetic disc. The magnetic head slider is supported by a leading end of an arm shaped head suspension, and relatively moves with respect to the magnetic disc by the driving operation of a voice coil motor. Accordingly, the magnetic disc drive carries out a positioning control making the magnetic head slider follow to a target track, by driving the voice coil motor in correspondence to the read servo data.
In the magnetic disc drive mentioned above, in order to improve a track density of the magnetic disc, it is necessary to enhance a servo band width of the positioning control so as to make a precision of the positioning of the magnetic head slider high. However, due to existence of a resonance frequency of the head suspension transmitting the motion of the voice coil motor to the magnetic head slider, it is hard to enhance the servo band width of the positioning control.
In order to solve the problem, there has been proposed a so-called two-stage actuator type magnetic disc drive, in which a micro actuator is provided at a position which is closer to the magnetic head slider than the voice coil motor. The micro actuator is provided in a midstream of the head suspension, or between the head suspension and the magnetic head slider, and achieves a high-precision positioning by finely positioning the magnetic head slider.
Further, a technique for incorporating a piezo element as a micro actuator into a magnetic head slider is disclosed in FIG. 23 of patent document 1 (JP-A-10-293979). In this magnetic head slider, a tabular piezo element is pinched between a slider substrate and an element substrate including a recording and reproducing element, and the element substrate including the recording and reproducing element is finely moved with respect to the slider substrate, by driving the piezo element.
However, in the case that the piezo element is used as a micro actuator, it is necessary to raise the power voltage driving the piezo element, and a structure of the apparatus becomes complicated. Further, incorporating the piezo element into the magnetic head slider has a lot of problems in manufacturing, and has not been put to practical use yet.